Molecular nature of sulfhydryl modification by hydrogen peroxide on type 1 ryanodine receptor

Aim： To elucidate the molecular nature of sulfhydryl modification by hydrogen peroxide on type 1 ryanodine receptor （RyR 1）. Methods： Rabbit skeletal muscle sarcoplasmic reticulum was treated with hydrogen peroxide, then RyR1 complex was isolated. The proteins in the complex were analysed by electrophoresis, Western blot and electron microscopy. Results： （1） Hydrogen peroxide induces inter-subunit cross-linking within the tetrameric RyR1 molecule; （2） in parallel to inter-subunit cross-linking, the RyR 1 molecule changes morphology; （3） the chemical and morphological changes are reversible： upon reduction by reducing agents, the RyR1 molecule regains its original state. Conclusion： These findings suggest that the molecular mechanism of RyR1 channel activity in sarcoplasmic reticulum regulated by hydrogen peroxide is through inter-subunit cross-linking within the tetrameric RyR 1 molecule, which in turn induces structural changes of RyR 1.